Silicon-based transducer for use in hearing instruments and listening devices

ABSTRACT

A silicon-based transducer assembly coupled to a movable structure in a hearing instrument. The transducer assembly includes at least one microphone chip and an ASIC having multiple integrated components such as any combination of a DSP, an A/D converter, an amplifier, a filter, or a wireless interface. The movable structure may be a battery access door, a volume dial, a switch, or a touch pad. A protection strip can be disposed across the battery access door to prevent debris from clogging the silicon-based transducer assembly. The transducer assembly may also include an array of microphone chips to achieve adaptive beam steering or directionality. When equipped with a wireless interface, the hearing instrument wirelessly communicates with another hearing instrument or with a network.

FIELD OF THE INVENTION

[0001] The present invention relates generally to silicon-basedtransducers, and more particularly, to silicon-based transducers for usein hearing instruments and listening devices.

BACKGROUND OF THE INVENTION

[0002] A hearing instrument usually consists of a shell which is shapedto fit inconspicuously into an ear canal or behind an ear. The shellgenerally accommodates a microphone, a receiver (speaker), an amplifieror a DSP, and a battery. The microphone is typically of the electretcondenser type, and the DSP or amplifier is ordinarily a separatecomponent which must be hardwired to the other components of the hearinginstrument. Producing a hearing instrument requires balancing severalcompeting considerations including the volume and shape of the shell,cost, and the desired functions to be incorporated into the hearinginstrument.

[0003] Fabrication of precision-machined electret condenser microphones(ECMs) is a relatively time- and labor-intensive process, and variationsin uniformity and reliability pose challenges relative to the design andperformance of microphones or transducer assemblies. For example,directional microphone applications using a matched pair require precisetolerances so as to avoid the undesired influences of sensitivitymismatching. The use of wires to connect components together inside ahearing instrument poses further challenges. Connecting wires is alabor-intensive process, and they are susceptible to electromagneticinterference which can adversely affect performance.

[0004] Many of the challenges posed by ECMs have been overcome with theadvent of silicon-based transducers which are fabricated usingmicroelectromechanical systems (MEMS) technology. A batch of thesetransducers can be fabricated on a single wafer, increasing uniformityand lowering production costs. They can also be surface mounted to asubstrate by standard solder reflow techniques, thereby obviating theuse of wires conventionally used with ECMs.

[0005] Multiple microphones can be arrayed to provide directionality oradaptive beam steering. In a conventional microphone array, such as amatched pair, each ECM in the array must be precision machined so as tohave nearly identical sensitivity and/or response characteristics foroptimal performance. Moreover, each additional ECM consumes more space,which poses yet additional design challenges.

[0006] Silicon-based transducers offer numerous advantages andcharacteristics including a small space consumption, uniformity, andreliability, for example. The present invention is directed toexploiting these advantages in hearing instruments and otherapplications.

SUMMARY OF THE INVENTION

[0007] According to one embodiment of the present invention, a hearinginstrument includes a housing, a manually movable structure disposedadjacent an exposed portion of the housing, and a silicon-basedtransducer assembly mechanically or electrically coupled to the manuallymovable structure. The silicon-based transducer assembly includes anASIC which includes any combination of an A/D converter, a D/Aconverter, a DSP, an amplifier, a preamplifier, a voltage stabilizer, acharge pump (also called voltage stepper or voltage upconversion), animpedance correction circuit, an oscillator, a filter, or a wirelessinterface. The transducer assembly also includes at least onesilicon-based microphone. The manually movable structure is, indifferent embodiments, an access door, a rotatable dial, a switch, atouch pad, a flex-print or a printed circuit board.

[0008] In another embodiment, the silicon-based transducer assemblyincludes a wireless interface. The transducer assembly can also beincorporated into a disposable hearing instrument.

[0009] An array of silicon-based microphones is incorporated in ahearing instrument to increase overall signal-to-noise ratio, to achievedirectionality, or to provide adaptive beam steering.

[0010] The above summary of the present invention is not intended torepresent each embodiment, or every aspect, of the present invention.This is the purpose of the figures and the detailed description whichfollow.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The foregoing and other advantages of the invention will becomeapparent upon reading the following detailed description and uponreference to the drawings.

[0012]FIG. 1A is a cutaway perspective view of a silicon-basedtransducer assembly suitable for use in the present invention.

[0013]FIG. 1B is a cutaway perspective view of another silicon-basedtransducer assembly suitable for use in the present invention.

[0014]FIG. 1C is a top view of an array of silicon-based transducerassemblies arranged on a substrate.

[0015]FIG. 2A is an exploded perspective view of a hearing instrumenthaving an access door as a movable structure.

[0016]FIG. 2B is a cross-sectional view of the hearing instrument shownin FIG. 2A with the access door disposed in a closed position.

[0017]FIG. 2C is an exploded perspective view of a hearing instrumenthaving a different access door from that shown in FIG. 2A as a movablestructure.

[0018]FIG. 2D is a cross-sectional view of the hearing instrument shownin FIG. 2C with the access door disposed in a closed position.

[0019]FIG. 2E is a partial cutaway perspective view of a hearinginstrument having an access door with a silicon-based transducerassembly incorporated therein on a flexprint and a horizontally mountedbattery.

[0020]FIG. 2F is a partial cutaway perspective view of a hearinginstrument having an access door with a silicon-based transducerassembly incorporated therein on a flexprint and a vertically mountedbattery.

[0021]FIG. 2G is a partial cutaway perspective view of two silicon-basedtransducer assemblies injection molded into a battery access door of ahearing instrument.

[0022]FIG. 2H is a partial cutaway perspective view of a silicon-basedtransducer assembly injection molded into a battery access door of ahearing instrument.

[0023]FIG. 3 is an exploded perspective view of a hearing instrumenthaving a rotatable dial as a movable structure.

[0024]FIG. 3A is a cross-sectional view of the rotatable dial of thehearing instrument shown in FIG. 3.

[0025]FIG. 3B is a perspective view of a faceplate of a hearinginstrument showing a protection strip covering a closed battery accessdoor.

[0026]FIG. 3C is a perspective view of the faceplate shown in FIG. 3Bshowing a position of the protection strip when the battery access dooris opened.

[0027]FIG. 4 is a perspective cutaway view of a hearing aid having atoggle switch as a movable structure.

[0028]FIG. 5 is a block diagram of a wireless system according to aspecific aspect of the present invention.

[0029]FIG. 6 is a flow chart diagram of methods of assembling a hearinginstrument according to specific aspects of the present invention.

[0030] While the invention is susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and will be described in detail herein. Itshould be understood, however, that the invention is not intended to belimited to the particular forms disclosed. Rather, the invention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0031]FIG. 1A is a cutaway perspective view of a silicon-basedtransducer assembly 20 which generally includes a transducer chip 24coplanar with an integrated circuit (IC) chip 26, an intermediate chip28 disposed adjacent the transducer chip 24 and the IC chip 26. Thetransducer chip 24 includes a diaphragm 32 and backplate 34, which maybe placed on either side of the diaphragm 32. A seal ring 36 surroundsthe diaphragm 32 and backplate 34 to form a backchamber 38.Redistribution circuits on the intermediate chip 28 electrically connectthe diaphragm 32 and backplate 34 to the IC chip 26. Pads 42 or solderbumps are disposed on an exposed surface of the intermediate chip 28 asshown for connection to external components such as a battery (notshown), an amplifier (not shown) or DSP (not shown), a wirelessinterface (not shown) or a receiver (not shown). The pads 42 areconnected to the transducer chip and/or the ASIC via feedthroughsrunning through the feedthrough opening 40. Feedthrough connections canalso be made through several feedthrough openings or through closedelectrical feedthroughs. The transducer chip 24, the IC chip 26, and theintermediate chip 28 are silicon-based, i.e., include silicon in theircomposition.

[0032] The transducer assembly 20 is fabricated according tomicroelectromechanical system (MEMS) technology and optionally includesCMOS structures. As is known, a plurality of transducer assemblies maybe batch processed on a single wafer. Their structure and fabricationare well known to those skilled in the art.

[0033]FIG. 1B illustrates a cutaway perspective view of a silicon-basedtransducer assembly 52 in a stacked arrangement. The transducer assembly52 generally includes an intermediate chip 57 and a transducer chip 54and an IC chip 56 flip-mounted to the intermediate chip 57 preferablyusing a fluxless soldering technique. An opening in the transducer chip54 is covered by a movable diaphragm 60 and a backplate 62 whichtogether form a capacitor whose capacitance varies as the diaphragm ismoved in response to incident sound. The changes in capacitance areprovided to the IC chip 56 via a feedthrough conductors 63. Thefeedthrough conductors 63 are coupled to the diaphragm 60 and backplate62 by solder bumps 64 and to the IC chip 56 by interconnects 66, whichcould also be solder bumps. A seal ring 68 surrounds the diaphragm 60and backplate 62. Additional details of the transducer assembly 52 shownin FIG. 1B are described and shown in U.S. Pat. No. 6,088,463, titled“Solid State Silicon-Based Condenser Microphone,” issued Jul. 11, 2000,which is incorporated herein by reference in its entirety. It should benoted that the transducer assemblies shown in FIGS. 1A and 1B areexemplary, and that any other suitable silicon-based transducer assemblymay be employed.

[0034] Silicon-based transducers can be batch processed on a singlewafer in large quantities, and accordingly, each transducer is highlymatched with the other transducers on the same wafer and even ondifferent wafers. As a result, the silicon-based transducers remainstable over long periods of time and are relatively immune to undesiredeffects of temperature and humidity. These characteristics ofsilicon-based transducers make them attractive candidates for use in anarray, such as a matched pair, and their relatively small sizeeliminates the space constraint challenges posed by the larger-sizedlegacy ECMs.

[0035]FIG. 1C illustrates four silicon-based transducer assemblies 80 a,80 b, 80 c, 80 d arrayed (i.e., arranged in predetermined manner) on aprinted circuit board 82. Alternately, they may be arrayed on aflex-print. Each of the transducer assemblies may be the transducerassembly 20 shown in FIG. 1A or the transducer assembly 52 shown in FIG.1B or any other suitable silicon-based transducer assembly. In apreferred embodiment, each of the transducer assemblies 80 a-d arefabricated from the same wafer to minimize variations in uniformityamong transducer assemblies, however, the transducer assemblies 80a-dmay be fabricated from different wafers. Note that the traces shown onthe printed circuit board 82 are for illustrative purposes only, and arenot meant to show actual placement of the traces.

[0036] In alternate embodiments, fewer or more than four silicon-basedtransducer assemblies may be employed without departing from the scopeof the present invention. The array of transducer assemblies 80 can beadapted to provide beam forming or adaptive beam steering according toconventionally known techniques.

[0037] The array of silicon-based transducer assemblies 80 can beadapted to achieve directionality, particularly at high frequencies(such as above 4 kHz). Directionality can be achieved through beamforming using a matched-pair microphone or a microphone array. Thesilicon-based microphones described in connection with FIGS. 1A and 1Bare well suited for matched-pair or array applications because they canbe uniformly and reliably batch produced on a single wafer therebyreducing variations in sensitivity and phase responses from onemicrophone to another. Alternately, matched pair microphones ormicrophone arrays can be fabricated as a single assembly on a siliconwafer using MEMS-based fabrications techniques and including a shared ICchip. In one embodiment, two silicon-based transducer assemblies eachhaving an output are provided on a substrate, and one output is timedelayed and inverted to produce a delayed signal. The delayed signal issummed with the other output to produce a summed signal which isprovided to processing circuitry for processing the summed signal. In analternate embodiment, more than two silicon-based transducer assembliesare employed to achieve directionality.

[0038] As is known, signal-to-noise ratio can be increased by combiningthe outputs of multiple microphones. However space constraints due tothe size of conventional electret condenser microphones and variationsin manufacturing posed design challenges. The relatively miniature sizeof silicon-based transducers and batch processing capabilities relievethose design challenges, and therefore higher signal-to-noise ratios,are more easily achieved by combining the outputs of multiple transducerassemblies.

[0039] In a preferred embodiment, the 1C chip 26 or the 1C chip 56described in connection with FIGS. 1A and 1B, respectively, is anapplication specific integrated circuit (ASIC). The ASIC preferablyincludes CMOS structures. The ASIC includes any combination of one ormore of the following conventionally known circuit components: ananalog-to-digital converter, a digital-to-analog converter, a digitalsignal processor (DSP), a microprocessor, a preamplifier, a Class-Damplifier, a voltage stabilizer, a charge pump, an impedance correctioncircuit, an oscillator, a filter such as a low-frequency roll-offfilter, an oscillator, and a wireless interface. The wireless interfaceincludes a receiver and a transmitter for receiving and transmittingwireless signals, respectively, and optionally includes a modem. TheClass-D amplifier may be a pulse width modulated (PWM) or pulse densitymodulated (PDM) amplifier. The transducer assemblies of FIGS. 1A and 1Bmay include one or several sensors and/or actuators. Such sensor may beadapted to detect any combination of temperature, humidity,acceleration, rotation, tilt, pressure, finger touch, or movement. Theoutput of the sensor is provided to compensation circuitry adapted tocompensate for changes in the ambient. An actuator may include areceiver (speaker) or a switch.

[0040] A high-frequency roll-off filter is achieved by placing acapacitor (not shown) over the appropriate pads 42 corresponding to theoutputs of the transducer chip 24 or 54. Alternately, the capacitor maybe integrated into the intermediate chip 28 or 57 or into the IC chip 26or 56.

[0041] Note that the use of the term “arrayed” to describe thearrangement of silicon-based transducer assemblies is not intended toconvey that the assemblies must be arranged in rows and columns. Forexample, an odd number of assemblies may be arranged in a predeterminedfashion on the printed circuit board 82.

[0042] The array of silicon-based transducer assemblies 80 may beconnected in parallel via a 3- or 4-wire low-voltage, low-power systembus, such as the system bus described in commonly owned, U.S. patentapplication Ser. No. 60/416,952, titled “Digital System Bus For Use inLow Power Instruments Such As Hearing Aids And Listening Devices,” whichis incorporated herein by reference in its entirety. An appropriateinterface is integrated into the silicon-based transducer assembly forproper application of the system bus.

[0043] Turning now to FIG. 2A, there is shown an exploded, perspectiveview of a hearing instrument 200 in accordance with one aspect of thepresent invention. The hearing instrument 200 generally includes ahousing 202, a faceplate 204, a manually movable access door 206, and aretrieval line 208. The faceplate 204 has an opening 210 shaped toreceive the access door 206. The access door 206 is hingedly connectedto the housing 202 when a clip portion 212 of the access door 206 ismated with a pin 214 as shown in FIG- 2B. The retrieval line 208 can begrasped by the wearer of the hearing instrument 200 to facilitateremoval thereof from the ear canal. In one embodiment, the access door206 provides access to a battery (not shown).

[0044]FIG. 2B is a cross-sectional view of the hearing instrument 200showing the placement of a silicon-based transducer assembly 220installed in the access door 206. In alternate embodiments, thesilicon-based transducer assembly 220 may be the transducer assembly 20shown in FIG. 1A, the transducer assembly 52 shown in FIG. 1B, or thearray of transducer assemblies 80 shown in FIG. 1C. The aperture 216 inthe access door 206 permits access of sound to the transducer assembly220. In an embodiment where an array of transducer assemblies isinstalled in the access door 206, apertures are formed in the accessdoor 206 to permit access of sound to each of the transducer assemblies.The transducer assembly 220 may optionally be coupled to a printedcircuit board or flex-print. Connections to a power supply, such as abattery, from the transducer assembly 220 are made by conventionaltechniques known to those skilled in the art. Such connections may berealized, for example, by using pads, wires, traces, solder bumps, or acombination thereof.

[0045]FIG. 2C shows a hearing instrument 250 having a housing 252 and amanually movable access door 254 disposed adjacent an opening 256 in afaceplate 258 and hingedly connected thereto by pins 260, 262. Thefaceplate 258 is attached to the housing 252 or may be integrally formedas part of the housing 252. A silicon-based transducer assembly 264 isdisposed in the access door 254 as shown in FIG. 2D and is manuallymovable with the access door 254. The silicon-based transducer assembly264 may be the transducer assembly 20 shown in FIG. 1A, the transducerassembly 52 shown in FIG. 1B, or the array of transducer assemblies 80shown in FIG. 1C. The transducer assembly 264 may optionally be coupledto a printed circuit board or flex-print. Connections to a power supply,such as a battery 257, from the transducer assembly 264 are made byconventional techniques known to those skilled in the art.

[0046]FIG. 2E is a partial cutaway perspective view of a hearinginstrument 230 according to another embodiment of the present invention.The hearing instrument 230 a generally includes a housing 232 a, afaceplate 234 a, a battery access door 236 a, a silicon-based transducerassembly 238 a, and a receiver (speaker) 240 a. The battery access door236 a is shown as transparent and partially ajar for ease ofillustration, and is manually movable between an open and closedposition. The silicon-based transducer assembly 238 a is mounted on aflexprint 242 a which electrically couples the transducer assembly 238 ato a control 244 a, a battery 246 a, and the receiver 240 a. The battery246 a is also shown as transparent for ease of illustration. Note thatthe transducer assembly 238 a is movable with the access door 236 a. Theaccess door 236 a is hingedly connected to the faceplate 234 a tofacilitate installation and removal of the battery 246 a. The control244 a is a push button, though in other embodiments, it may be a volumedial, a toggle switch, a touch pad, or the like for adjusting hearinginstrument parameters such as volume, sensitivity, directionality,frequency response, and gain.

[0047] The hearing instrument 230 a also includes a connector 241 acoupled to the flexprint 242 a. The connector 241 a is adapted toreceive an externally provided programming strip 243 a which is composedof a flexprint or substrate that carries a plurality of terminals 245 a.The number of terminals 245 a may vary from the illustration. Theprogramming strip 243 a is used to program any combination ofcharacteristics of the hearing instrument 230 a. These characteristicsinclude sensitivity, frequency response, gain, and directionality. Tocause the hearing instrument 230 a to be programmed, the programmingstrip 243 a is inserted into the connector 241 a. Programminginstructions are communicated between a programming unit (not shown) andthe hearing instrument 230 a along the flexprint 242 a according toconventionally known techniques. The power during programming may besupplied by the battery 246 a or the programming unit.

[0048]FIG. 2F illustrates a hearing instrument 230 b having a differentbattery access door 236 b according to another embodiment of the presentinvention. The hearing instrument 230 b generally includes a housing 232b, a faceplate 234 b, a battery access door 236 b, a silicon-basedtransducer assembly 238 b, and a receiver (speaker) 240 b. The batteryaccess door 236 b holds a battery 246 b as shown and includes a control244 b for adjusting parameters of the hearing instrument 230 b. Thebattery access door 236 b is manually movable between an open and closedposition. A flexprint 242 b electrically couples a silicon-basedtransducer assembly 238 b to the control 244 b, the battery 246 b, andthe receiver 240 b.

[0049] The hearing instrument 230 b also includes a connector 241 bwhich receives a programming strip 243 b carrying a plurality ofterminals 245 b. The hearing instrument 230 b also includes a retrievalline 247 b to facilitate insertion and removal of the hearing instrument230 b relative to the operator's ear canal. In an embodiment, theretrieval line 247 b also functions as an antenna to communicatewireless data between the hearing instrument 230 b and another system,such as another hearing instrument or a network. The wirelesscommunication is described in further detail with reference to FIG. 5.

[0050]FIG. 2G is an illustration of two silicon-based transducerassemblies mounted into a battery door of a hearing instrument 230 c byinjection molding techniques. The hearing instrument 230 c includes atwo-piece, manually movable access door 236 c composed of a cap 231 cand a support piece 233 c. A flexprint 242 c is sandwiched between thecap 231 c and the support piece 233 c, and a first silicon-basedtransducer assembly 238 c and a second silicon-based transducer assembly239 c are electrically coupled to the flexprint 242 c. The flexprint 242c depends into the hearing instrument 230 c to connect a receiver(speaker). Connections to the battery 246 c are made according toconventionally known techniques.

[0051]FIG. 2H is identical to FIG. 2G except that only one silicon-basedtransducer assembly is shown. A hearing instrument 230 d includes atwo-piece, manually movable access door 236 d composed of a cap 231 dand a support piece 233 d. A flexprint 242 d is sandwiched between thecap 231 d and the support piece 233 d, and a silicon-based transducerassembly 238 d is electrically coupled to the flexprint 242 d. Theflexprint 242 d depends into the hearing instrument 230 d to connect areceiver (speaker). Connections to the battery 246 d are made accordingto conventionally known techniques.

[0052] The connection between the faceplate and battery access doorshown in FIGS. 2A-2H may be modified to provide vibration isolation byforming a suspension between the faceplate and battery access door.Because the combined mass of the battery access door and the battery isrelatively high, a reasonably stiff suspension would obtain a relativelylow resonance frequency (around a couple of 100 Hz), which improvesperformance in the 2-3 kHz range. The suspension is preferably formedalong the hinge connecting the battery access door to the faceplate andalong the portion of faceplate that holds the battery door in a secureposition such that the battery access door “sits up” or is suspendedfrom the faceplate so that vibrations are transmitted via the suspensionto the access door.

[0053] Another feature of the access doors shown in FIGS. 2A-2H is thatthey are easily replaced and repaired without having to send the hearinginstrument back to the factory. Replacement and/or repair of the hearinginstrument can be done by the user. Preferably, the battery access dooris coupled to the faceplate or housing of the hearing instrument by asolderless connection, permitting easy replacement and repair of adamaged component. For example, if the silicon-based transducer becomesdamaged, the user can order a replacement access door containing a newsilicon-based transducer from the factory. The factory would mail areplacement access door with integrated transducer to the user withappropriate instructions. In this manner, a user's hearing instrumentmay also be upgraded, for example, to a hearing instrument capable ofachieving directionality.

[0054]FIG. 3 shows a manually movable dial 306 which is secured to ahousing 304 of a hearing instrument 300. The dial 306 includes anaperture 302 and a silicon-based transducer assembly 308 disposedadjacent the aperture 302 in the dial 306 as shown in FIG. 3A. The dial306 is movable in a rotational direction to adjust a characteristic ofthe hearing instrument 300, such as volume or sensitivity. Thetransducer assembly 308 is the transducer assembly 20 shown in FIG. 1A,though in alternate embodiments, the transducer assembly 308 may be thetransducer assembly 52 shown in FIG. 1B, or the array of transducerassemblies 80 shown in FIG. 1C. In the latter alternate embodiment thatincludes an array of transducer assemblies, the dial 302 includes aplurality of apertures positioned and dimensioned to permit access ofsound to each of the corresponding transducer assemblies.

[0055]FIGS. 3B and 3C illustrate different views of a faceplate 310 of ahearing instrument having a protection strip 318 (shown as transparentfor ease of illustration) disposed across a battery access door 312. Asilicon-based transducer assembly 316 is integrated into the batteryaccess door 312 in accordance with any embodiment described above. Theprotection strip 318 is secured to the faceplate 310 by a connection 320using an adhesive, a clamping member, or the like. When the batteryaccess door 312 is in a closed position (as shown in FIG. 3B), theprotection strip 318 covers and protects the silicon-based transducerassembly 316 and permits sound access via a grid 322 which is formed inthe area that coincides with the sound access area of the silicon-basedtransducer. The protection strip 318 is preferably composed of the samematerial as the faceplate 310 such as plastic (Kapton), or any othersuitable material.

[0056] The holes in the grid 322 are dimensioned so as to criticallydamp the microphone to have an acoustic roll-off above 10 kHz to preventspurious signals above 10 GHz (such as signals from ultrasonic alarmsystems, garage door openers, and the like) from adversely affecting theinternal electronics of the hearing instrument. In addition, variousparameters of the hearing instrument can be programmed by altering theamount, dimensions, and positions of the holes in the grid 322 as wellas by altering the thickness of the protection strip 318. Accordingly,the protection strip 318 can be easily replaced with another byde-attaching the protection strip 318 from its connection 320.Additional parameters may be adjusted via a control dial 314 mounted tothe faceplate 310.

[0057] As can be seen from FIG. 3C, when the battery access door 312 isopened to reveal a battery 324, the grid 322 of the protection strip 318is extended beyond the battery access door 312 in the direction of arrowA. The extended portion of the protection strip 318 can then be peeledaway from the battery access door 312 to clean the grid 322 of anydebris that may have accumulated in the holes of the grid 322. Theability to clean the grid 322 is particularly useful for wearers ofhearing aids who also use hairspray or work in dusty environments.Alternately, the protection strip 318 can be simply be replaced insteadof cleaned by detaching the protection strip 318 from the connection 320as described earlier and reattaching a replacement strip. After cleaningthe grid 322 of the protection strip 318, the battery access door 312 isclosed, and power to the internal circuitry of the hearing instrument isrestored via terminals 326 a,b.

[0058] In FIG. 4, the movable structure is a switch 402, which issecured to a housing 404 of a hearing instrument 400. The switch 402includes a base portion 405 and a protruding portion 406. Asilicon-based transducer assembly 408 is disposed in the protrudingportion 406 of the switch 402. An aperture 410 is formed at the exposedend of the protruding portion 406 to permit access of sound to thetransducer assembly 408 as shown. The transducer assembly 408 is thetransducer assembly 20 shown in FIG. 1A, though in alternateembodiments, the transducer assembly 408 may be the transducer assembly52 shown in FIG. 1B, or the array of transducer assemblies 80 shown inFIG. 1C.

[0059] Although the transducer assembly 408 is shown in the protrudingportion 406 of the switch 402, the protruding portion 406 could bereplaced by the transducer assembly 408 and an optional substrate sothat the transducer assembly 408 forms a protruding portion. Inalternate embodiments, the switch 402 may be of the toggle, rotary, orpushbutton type. In the case of a toggle or rotary switch, thetransducer assembly 408 may be disposed in any position in theprotruding portion or may itself form the protruding portion. In thecase of a pushbutton switch, the transducer assembly may be disposed inthe depressable portion of the pushbutton or may itself form thedepressable portion.

[0060] In yet another embodiment of the present invention, the movablestructure is a touch pad disposed over an opening or cavity in a housingof a hearing instrument. A silicon-based transducer assembly, such asthe transducer assembly 20 shown in FIG. 1A, is disposed adjacent thetouch pad which includes an aperture to permit access of sound to thetransducer assembly. As is known, a touch pad typically includes twotransparent films separated by a nonconducting material to maintain adistance between the two films. When the two films are pressed together,driver circuitry and associated software detect the location of touchand perform a programmed function. In this manner, the touch padoperates as a switch, and may be programmed to perform a certainfunction when the touch pad is touched.

[0061] In alternate embodiments, the function may be turning the hearinginstrument on or off, switching the hearing instrument to a telecoilmode, switching to wireless mode as described in connection with FIG. 5,switching to a different acoustic environment mode, changingdirectionality profiles, or regulating the volume. In addition, bycontinuously monitoring the touch locations, the driver circuitry andsoftware can detect direction. Thus, when the operator runs a fingeralong the surface of the touch pad in a certain direction, the directionof movement is interpreted by software and a function is performed, suchas lowering or raising volume, raising or lowering sensitivity. Thetouch pad embodiment may be adapted for use in a Behind-The-Ear hearinginstrument, though it is also suitable for use in a hearing instrumentof the Completely-In-Canal, In-the-Canal, or In-The-Ear type.

[0062] The hearing instruments 200, 250, 300, 400 shown in FIGS. 2A to 4are hearing aids of the Completely-In-Canal type, although in alternateembodiments, they may be of the In-the-Canal, In-the-Ear, orBehind-the-Ear type. Although a faceplate is shown in the hearinginstruments illustrated in FIGS. 2A to 4, it is understood that in otherembodiments, the faceplate may be eliminated and the movable structuredisposed in an opening or cavity in the housing of the hearinginstrument without departing from the scope of the present invention. Inone embodiment, the shell and manually movable structures shown in FIGS.2A to 4 are made by conventional SLA (stereolithography) techniques. Themanually movable structure (e.g., battery access door) is built up usingstereolithography techniques leaving an opening for a modules containingthe working elements of the hearing instrument. This approach simplifiesthe manufacturing process, and avoids using multiple techniques to formthe housing of the hearing instrument.

[0063] In other embodiments, the shape of the manually movable structureis customized using stereolithography techniques to optimize theplacement of the silicon-based transducer(s) for each individual wearer.Because the silicon-based transducer is coupled to the manually movablestructure, the shape of the manually movable structure (such as more orless convex), the position and number of the silicon-based transducers,and ridges and other deformations on the manually movable structure canbe adjusted or formed to compensate for diffraction and ear and headgeometry of each individual wearer and to make directionality possiblefor hearing instruments.

[0064] The conductive wires to connect the silicon-based transducer toother working components of the hearing instrument may also beintegrated by using stereolithography. Because the wires are in placebefore assembly, the silicon-based transducers can be easily insertedand replaced. It should be noted that the conductive wires may be madeof conductive rubber.

[0065] Any of the transducer assemblies shown and described inconnection with the foregoing may operate as a switch by detectingtransients in air pressure induced by touching the sound inlet of thetransducer assembly. Because the transients in pressure would be higherthan typical sound pressures, they can be detected by detecting anoverload or collapse of the membrane.

[0066] It should be noted that the hearing instruments described abovemay be adapted to be disposable. Disposable hearing instruments shouldbe relatively inexpensive to increase their attractiveness. Lower costsmay be achieved by reducing the functional components in the ASIC,fixing the battery in the housing without providing an access door,using cheaper materials, or using silicon-based microphones that do notentirely meet quality control standards but are still functional.

[0067] The teachings of the present invention extend to other devicesbesides hearing instruments such as hearing aids. For example, thepresent invention contemplates any device capable of transducing betweenacoustic signals and corresponding electrical signals, such as anearphone, a headphone, or a headset, for example. Any of the embodimentsdescribed herein may be incorporated into any such device. Accordingly,a silicon-based transducer may be a silicon-based microphone or asilicon-based receiver (speaker), depending upon the application.

[0068]FIG. 5 illustrates a block diagram of a wireless system 700 thatgenerally includes a hearing instrument 702 a, an optional hearinginstrument 702 b, and a network 704. The hearing instruments 702 a,b maybe any of the hearing instruments described above, and include asilicon-based transducer assembly 706 a,b, an ASIC 708 a,b, and awireless interface 710 a,b, respectively. The silicon-based transducerassemblies 706 a,b may be any of the transducer assemblies described inconnection with FIGS. 1A to 1C. In another embodiment, the silicon-basedtransducer assemblies 706 a,b are silicon-based receivers. The wirelessinterfaces 710 a,b are coupled to antennas 712 a,b, respectively. Thenetwork 704 is coupled to an antenna 714. In a specific embodiment, thewireless interfaces 710 a,b are short-range RF links. The wirelessinterfaces 710 a,b also include conventional transceivers and modems forenabling wireless communication.

[0069] As shown in FIG. 5, wireless communication may be establishedbetween the hearing instruments 702 a, 702 b and the network 704 orbetween the hearing instrument 702 a and the hearing instrument 702 b tocommunicate wireless data therebetween. The wireless data may bemodulated according to any conventionally known modulation technique,and may be transmitted or received on carriers in any suitable frequencyrange, such as Bluetooth, 802.11, cellular, RF, and so forth.

[0070] In one embodiment, the network 704 communicates wireless data tothe hearing instrument 702 a in the form of modulated audio signals. Inthis embodiment, the network 704 broadcasts specific audio data over thewireless spectrum to hearing instruments which are adapted for wirelesscommunications. In this manner, for example, a hearing impaired personsitting in the back of a large conference room may comfortably hear adistant speaker, or an undercover agent may discretely receiveinstructions from a remote operator without compromising his cover.

[0071] In another embodiment, the network 704 communicates wireless datato the hearing instrument 702 a in the form of programming instructions.The programming instructions contain data which adjusts characteristicsof the hearing instrument 702 a. The characteristics includesensitivity, gain, frequency response, and directionality. Theprogramming may occur as the hearing instrument 702 a is worn by itsoperator, thus allowing the operator to hear the effects immediately.The programming instructions may also be used to program a differentfunction associated with a movable structure on the hearing instrument.For example, when the movable structure is a rotatable dial, such asdescribed in connection with FIGS. 3 and 3A, and adapted to change thevolume of a receiver, the programming instructions may program thefunction of the rotatable dial to change sensitivity or othercharacteristic of the hearing instrument. In the case where the movablestructure is a toggle switch, such as described in connection with FIG.4, the function(s) associated with the toggle switch may be alteredusing the programming instructions.

[0072] In still another embodiment, the hearing instrument 702 acommunicates wireless data between the hearing instrument 702 b. Forexample, this embodiment allows two hearing instruments worn by anoperator to communicate audio signals for improved directional or trulythree-dimensional hearing.

[0073] In yet another embodiment, the hearing instrument 702 a isprogrammed through ultrasound. The silicon-based transducer is sensitiveup to 100 kHz, which allows the hearing instrument 702 a to beprogrammed without additional cables, flex strips, RF devices, etc. Inthis embodiment, the silicon-based transducer assembly includes adigital filter to extract wireless data including audio data andprogramming information carried over ultrasound frequencies. Ultrasoundtransmission is improved by mounting the silicon-based transducerassembly in a manner described herein.

[0074]FIG. 6 is a flow chart of a method of assembling a hearinginstrument according to the present invention. It should be noted thatalthough the steps are shown in FIG. 6 in a particular order, the stepsmay be performed in any order without departing from the scope of thepresent invention. At step 800, a housing is provided. In oneembodiment, a faceplate having an opening is attached to the housing atstep 802. A moveable structure is secured adjacent the opening at step804, and at step 806, a silicon-based transducer assembly is coupled tothe moveable structure. In another embodiment, a silicon-basedtransducer assembly is mounted to a substrate at step 808, and thesubstrate is attached as a moveable structure to the housing at step810.

[0075] The housing, faceplate, moveable structure, and silicon-basedtransducer assembly are described in further detail in connection withFIGS. 1A to 5 and may be used in various embodiments in accordance withthe method shown in FIG. 6.

[0076] While the present invention has been described with reference toone or more particular embodiments, those skilled in the art willrecognize that many changes may be made thereto without departing fromthe spirit and scope of the present invention. Each of these embodimentsand obvious variations thereof is contemplated as falling within thespirit and scope of the claimed invention, which is set forth in thefollowing claims.

What is claimed is:
 1. A hearing instrument, comprising: a housinghaving an exposed portion to the environment, the exposed portion havingan opening therethrough; a manually movable structure disposed in saidopening; and a silicon-based transducer assembly coupled to saidmanually movable structure.
 2. The hearing instrument of claim 1,wherein said manually movable structure is an access door, saidsilicon-based transducer assembly being secured to said access door,said access door having at least one aperture to permit access of soundto said silicon-based transducer assembly.
 3. The hearing instrument ofclaim 2, wherein said access door is hingedly coupled to said housing.4. The hearing instrument of claim 2, wherein said access door isremovably secured to said housing.
 5. The hearing instrument of claim 2,wherein said access door is formed by stereolithography.
 6. The hearinginstrument of claim 1, wherein said housing includes a faceplate, saidfaceplate being said exposed portion of said housing.
 7. The hearinginstrument of claim 1, wherein said manually movable structure is one ofan access door, a rotatable dial, a switch, a touch pad, a flex-print,and a printed circuit board.
 8. The hearing instrument of claim 7,wherein said switch is one of a toggle switch, a rotary switch, amomentary switch, and a pushbutton switch.
 9. The hearing instrument ofclaim 1, wherein said manually movable structure is adapted to be one ofrotated, toggled, flipped, hinged, pushed, pressed, and touched.
 10. Thehearing instrument of claim 1, wherein said silicon-based transducerassembly includes a silicon-based microphone formed according toMEMS-based technology.
 11. The hearing instrument of claim 10, whereinsaid microphone includes: a silicon-based transducer chip including abackplate and a diaphragm, said diaphragm being movable relative to saidbackplate in response to incident sound; an integrated-circuit chip forreceiving an electrical signal from said silicon-based transducer chipcorresponding to said incident sound; and an intermediate chip fixingsaid silicon-based transducer chip to said integrated-circuit chip in aspaced relationship, said intermediate chip including an electricalconductor coupling said integrated-circuit chip and said silicon-basedtransducer chip.
 12. The hearing instrument of claim 11, wherein saidintermediate chip and said integrated-circuit chip are generallycoplanar.
 13. The hearing instrument of claim 10, wherein saidintegrated-circuit chip is flip-chip mounted to said intermediate chip.14. The hearing instrument of claim 1, wherein said silicon-basedtransducer assembly includes a plurality of arrayed silicon-basedmicrophones.
 15. The hearing instrument of claim 14, wherein saidsilicon-based microphones are coupled together by a low-power,low-voltage system bus.
 16. The hearing instrument of claim 14, whereinsaid manually movable structure includes a plurality of apertures topermit access of sound to said plurality of silicon-based microphones.17. The hearing instrument of claim 14, wherein said plurality ofsilicon-based microphones are adapted to provide adaptive beam steering.18. The hearing instrument of claim 14, wherein the outputs of saidplurality of silicon-based microphones are combined to increasesignal-to-noise ratio.
 19. The hearing instrument of claim 14, whereinthe outputs of said plurality of silicon-based microphones are combinedto achieve high-frequency directionality.
 20. The hearing instrument ofclaim 1, wherein said silicon-based transducer assembly includeselectronics for processing electrical signals transduced from incidentsound.
 21. The hearing instrument of claim 20, wherein said electronicsinclude an ASIC.
 22. The hearing instrument of claim 20, wherein saidelectronics include at least one of an analog-to-digital converter, adigital-to-analog converter, a DSP, an amplifier, a preamplifier, avoltage stabilizer, a charge pump, an impedance correction circuit, anoscillator, a filter, and a wireless interface.
 23. The hearinginstrument of claim 22, wherein said filter is a low-frequency roll-offfilter.
 24. The hearing instrument of claim 22, wherein said wirelessinterface includes a transceiver.
 25. The hearing instrument of claim24, wherein said transducer assembly includes a silicon-based receiver.26. The hearing instrument of claim 22, wherein said wireless interfaceis an RF link.
 27. The hearing instrument of claim 22, wherein saidwireless interface is adapted to transfer wireless data between saidhearing instrument and a system.
 28. The hearing instrument of claim 27,wherein said system is a network.
 29. The hearing instrument of claim27, wherein said system is another hearing instrument.
 30. The hearinginstrument of claim 27, wherein said wireless data includes modulatedaudio signals.
 31. The hearing instrument of claim 27, wherein saidwireless data includes instructions for programming characteristics ofsaid hearing instrument.
 32. The hearing instrument of claim 27, whereinsaid wireless data is transferred through ultrasound.
 33. The hearinginstrument of claim 31, wherein said characteristics include one ofsensitivity, frequency response, gain, and directionality.
 34. Thehearing instrument of claim 1, wherein said hearing instrument is of astyle selected from the group consisting of Completely-in-the-Canal,In-the-Canal, In-the-Ear, and Behind-the-Ear.
 35. The hearing instrumentof claim 1, wherein said hearing instrument is adapted to be disposable.36. A hearing instrument, comprising: a housing; a faceplate attached tosaid housing and having an opening, a battery access door disposedadjacent said opening, and a silicon-based transducer chip secured tosaid battery access door.
 37. The hearing instrument of claim 36,wherein said battery access door includes an aperture to permit accessof sound to said silicon-based transducer chip.
 38. The hearinginstrument of claim 36, wherein said silicon-based transducer chipincludes a silicon-based microphone.
 39. The hearing instrument of claim38, wherein said silicon-based transducer chip includes an ASIC.
 40. Thehearing instrument of claim 38, wherein said silicon-based transducerchip includes a low-frequency roll-off filter.
 41. The hearinginstrument of claim 36, wherein said silicon-based transducer chipincludes a plurality of silicon-based microphones.
 42. The hearinginstrument of claim 36, wherein said battery access door is hingedlyconnected to said faceplate.
 43. The hearing instrument of claim 36,wherein said battery access door is movable between open and closedpositions.
 44. The hearing instrument of claim 36, further comprising aprotection strip movable with said battery access door and disposedacross at least a portion of said battery access door, said protectionstrip having a grid to permit access of sound to said silicon-basedtransducer chip.
 45. A method of assembling a hearing instrument,comprising: providing a housing; attaching a faceplate to said housing,said faceplate having an opening; disposing a cover assembly adjacentsaid opening; and mounting a silicon-based transducer assembly to saidcover assembly.
 46. The method of claim 45, wherein said cover assemblyincludes a cover, the method further comprising forming at least oneaperture in said cover to permit access of sound to said silicon-basedtransducer assembly.
 47. The method of claim 45, wherein said disposingis carried out using a hinge mechanism.
 48. The method of claim 45,wherein said silicon-based transducer assembly includes a plurality ofsilicon-based microphones, the method further comprising arraying saidsilicon-based microphones relative to said cover assembly.
 49. Themethod of claim 48, wherein said cover assembly includes a cover, themethod further comprising forming a plurality of apertures in said coverto permit access of sound to said plurality of silicon-basedmicrophones.
 50. The method of claim 48, further comprising combiningthe outputs of said plurality of silicon-based microphones to achievehigh-frequency directionality.
 51. The method of claim 45, wherein saidsilicon-based transducer assembly includes electronics for processingsignals indicative of acoustic energy.
 52. The method of claim 51,wherein said electronics include an ASIC.
 53. The method of claim 52,wherein said electronics include at least one of an analog-to-digitalconverter, a DSP, an amplifier, a voltage stabilizer, a charge pump, anoscillator, an impedance correction circuit, a filter, and a wirelessinterface.
 54. The method of claim 53, further comprising transferringwireless data via said wireless interface between said hearinginstrument and one of a network and another hearing instrument.
 55. Themethod of claim 54, wherein said wireless data includes instructions,the method further comprising programming said hearing instrument withsaid instructions.
 56. The method of claim 45, further comprisingadapting said hearing instrument to be disposable.